When I open minecraft a few minutes later in multiplayer the game keeps crashing i think it works fine in single player though.

---- Minecraft Crash Report ----
// Why did you do that?

Time: 7/3/13 3:54 PM
Description: Deserializing Message

java.lang.ClassCastException: com.google.gson.JsonPrimitive cannot be cast to com.google.gson.JsonObject
	at cw.a(SourceFile:14)
	at cw.deserialize(SourceFile:10)
	at com.google.gson.TreeTypeAdapter.read(TreeTypeAdapter.java:58)
	at com.google.gson.Gson.fromJson(Gson.java:795)
	at com.google.gson.Gson.fromJson(Gson.java:761)
	at com.google.gson.Gson.fromJson(Gson.java:710)
	at com.google.gson.Gson.fromJson(Gson.java:682)
	at cu.c(SourceFile:220)
	at bcn.a(SourceFile:518)
	at dl.a(SourceFile:49)
	at cn.b(SourceFile:350)
	at bcn.d(SourceFile:95)
	at bcu.b(SourceFile:60)
	at atn.k(SourceFile:1380)
	at atn.S(SourceFile:662)
	at atn.d(SourceFile:618)
	at net.minecraft.client.main.Main.main(SourceFile:101)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at cw.a(SourceFile:14)
	at cw.deserialize(SourceFile:10)
	at com.google.gson.TreeTypeAdapter.read(TreeTypeAdapter.java:58)
	at com.google.gson.Gson.fromJson(Gson.java:795)
	at com.google.gson.Gson.fromJson(Gson.java:761)
	at com.google.gson.Gson.fromJson(Gson.java:710)
	at com.google.gson.Gson.fromJson(Gson.java:682)

-- Serialized Message --
Details:
	JSON string: Cannot send chat message.
Stacktrace:
	at cu.c(SourceFile:220)
	at bcn.a(SourceFile:518)
	at dl.a(SourceFile:49)
	at cn.b(SourceFile:350)
	at bcn.d(SourceFile:95)

-- Affected level --
Details:
	Level name: MpServer
	All players: 4 total; [bcx['Sn0wpick'/2662581, l='MpServer', x=-95.93, y=65.62, z=610.22], ben['Justwait11'/986423, l='MpServer', x=-102.13, y=64.09, z=618.78], ben['Conky94'/2578469, l='MpServer', x=-102.94, y=64.00, z=620.31], ben['lalbea17'/2489990, l='MpServer', x=-102.84, y=64.91, z=605.75]]
	Chunk stats: MultiplayerChunkCache: 49
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-118,72,562), Chunk: (at 10,4,2 in -8,35; contains blocks -128,0,560 to -113,255,575), Region: (-1,1; contains chunks -32,32 to -1,63, blocks -512,0,512 to -1,255,1023)
	Level time: 1626595 game time, 1633063 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: true), thunder time: 0 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
	Forced entities: 23 total; [ben['Justwait11'/986423, l='MpServer', x=-102.13, y=64.09, z=618.78], ben['PonderousClock2'/2569178, l='MpServer', x=-133.09, y=65.00, z=645.47], bcx['Sn0wpick'/2662581, l='MpServer', x=-95.93, y=65.62, z=610.22], ben['Conky94'/2578469, l='MpServer', x=-102.94, y=64.00, z=620.31], ben['CreepyCraft'/1997701, l='MpServer', x=-138.84, y=69.16, z=671.47], ben['UDP_LAG'/1884603, l='MpServer', x=-145.53, y=66.06, z=649.93], ben['lalbea17'/2489990, l='MpServer', x=-102.84, y=64.91, z=605.75], ben['Conky94'/2578469, l='MpServer', x=-149.09, y=64.56, z=636.00], ben['Conky94'/2578469, l='MpServer', x=-102.94, y=64.00, z=620.31], ben['airsoftman8'/2181393, l='MpServer', x=-145.31, y=66.00, z=650.50], ben['Conky94'/2578469, l='MpServer', x=-133.53, y=65.74, z=648.24], ben['LeGiTmAn27'/2435345, l='MpServer', x=-146.46, y=65.22, z=651.14], ben['PonderousClock2'/2569178, l='MpServer', x=-76.67, y=66.99, z=600.84], ben['CRACRANOPAY'/2420328, l='MpServer', x=-149.35, y=66.41, z=650.71], ben['Justwait11'/986423, l='MpServer', x=-102.13, y=64.09, z=618.78], ben['PonderousClock2'/2569178, l='MpServer', x=-134.16, y=67.00, z=654.44], ben['Conky94'/2578469, l='MpServer', x=-105.39, y=64.00, z=635.02], ben['Justwait11'/986423, l='MpServer', x=-112.34, y=64.00, z=636.34], ben['Justwait11'/986423, l='MpServer', x=-108.99, y=64.00, z=631.42], ben['Conky94'/2578469, l='MpServer', x=-138.83, y=68.00, z=660.57], ben['lalbea17'/2489990, l='MpServer', x=-102.84, y=64.91, z=605.75], to['Skeleton'/2770143, l='MpServer', x=-81.50, y=41.00, z=620.50], ben['Miller1543'/2678787, l='MpServer', x=-106.31, y=75.19, z=617.13]]
	Retry entities: 0 total; []
Stacktrace:
	at bcu.a(SourceFile:284)
	at atn.k(SourceFile:1387)
	at atn.S(SourceFile:662)
	at atn.d(SourceFile:618)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- Affected level --
Details:
	Level name: MpServer
	All players: 4 total; [bcx['Sn0wpick'/2662581, l='MpServer', x=-95.93, y=65.62, z=610.22], ben['Justwait11'/986423, l='MpServer', x=-102.13, y=64.09, z=618.78], ben['Conky94'/2578469, l='MpServer', x=-102.94, y=64.00, z=620.31], ben['lalbea17'/2489990, l='MpServer', x=-102.84, y=64.91, z=605.75]]
	Chunk stats: MultiplayerChunkCache: 49
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-118,72,562), Chunk: (at 10,4,2 in -8,35; contains blocks -128,0,560 to -113,255,575), Region: (-1,1; contains chunks -32,32 to -1,63, blocks -512,0,512 to -1,255,1023)
	Level time: 1626595 game time, 1633063 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: true), thunder time: 0 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
	Forced entities: 23 total; [ben['Justwait11'/986423, l='MpServer', x=-102.13, y=64.09, z=618.78], ben['PonderousClock2'/2569178, l='MpServer', x=-133.09, y=65.00, z=645.47], bcx['Sn0wpick'/2662581, l='MpServer', x=-95.93, y=65.62, z=610.22], ben['Conky94'/2578469, l='MpServer', x=-102.94, y=64.00, z=620.31], ben['CreepyCraft'/1997701, l='MpServer', x=-138.84, y=69.16, z=671.47], ben['UDP_LAG'/1884603, l='MpServer', x=-145.53, y=66.06, z=649.93], ben['lalbea17'/2489990, l='MpServer', x=-102.84, y=64.91, z=605.75], ben['Conky94'/2578469, l='MpServer', x=-149.09, y=64.56, z=636.00], ben['Conky94'/2578469, l='MpServer', x=-102.94, y=64.00, z=620.31], ben['airsoftman8'/2181393, l='MpServer', x=-145.31, y=66.00, z=650.50], ben['Conky94'/2578469, l='MpServer', x=-133.53, y=65.74, z=648.24], ben['LeGiTmAn27'/2435345, l='MpServer', x=-146.46, y=65.22, z=651.14], ben['PonderousClock2'/2569178, l='MpServer', x=-76.67, y=66.99, z=600.84], ben['CRACRANOPAY'/2420328, l='MpServer', x=-149.35, y=66.41, z=650.71], ben['Justwait11'/986423, l='MpServer', x=-102.13, y=64.09, z=618.78], ben['PonderousClock2'/2569178, l='MpServer', x=-134.16, y=67.00, z=654.44], ben['Conky94'/2578469, l='MpServer', x=-105.39, y=64.00, z=635.02], ben['Justwait11'/986423, l='MpServer', x=-112.34, y=64.00, z=636.34], ben['Justwait11'/986423, l='MpServer', x=-108.99, y=64.00, z=631.42], ben['Conky94'/2578469, l='MpServer', x=-138.83, y=68.00, z=660.57], ben['lalbea17'/2489990, l='MpServer', x=-102.84, y=64.91, z=605.75], to['Skeleton'/2770143, l='MpServer', x=-81.50, y=41.00, z=620.50], ben['Miller1543'/2678787, l='MpServer', x=-106.31, y=75.19, z=617.13]]
	Retry entities: 0 total; []

-- System Details --
Details:
	Minecraft Version: 1.6.1
	Operating System: Windows 8 (x86)